This invention relates to a method of revising a profile, and more particularly, to a profile revising method for revising a profile generated by joining, in order, figure elements specified by figure definition statements in an automatic programming language.
In an automatic programming system for creating numerical control (NC) data using an automatic programming language such as APT (automatic programming tools) or FAPT.
A part program based on the automatic programming language is created by defining points, straight lines and circular arcs using simple symbols (this is referred to as "figure definition"), and then defining a tool path using the defined points, straight lines and circular arcs (referred to as "motion statement definition"). The part program based on the automatic programming language is subsequently converted into NC data comprising NC data (EIA codes or ISO codes) in a format capable of being executed by an NC unit.
For example, in the creation of a part program for moving a tool along a part profile A comprising straight lines and a circular arcs shown in FIG. 6(a), figure definition is performed by defining a point P.sub.1, straight lines S.sub.1, S.sub.2 and S.sub.3 and a circle Cl (see FIG. 6(b)), which are necessary for defining a part profile, as follows using a keyboard or tablet: EQU C.sub.1 =x.sub.3, y.sub.3, r.sub.1 ( 1) EQU P.sub.1 =x.sub.1, y.sub.1 ( 2) EQU P.sub.2 =x.sub.2, y.sub.2 ( 3) EQU S.sub.1 =P.sub.1,C.sub.1, L (4) EQU S.sub.2 =P.sub.2, C.sub.1, R (5) EQU S.sub.3 =P.sub.1, P.sub.2 ( 6)
Thereafter, the figure elements (which are displayed on a CRT screen) are picked in order, e.g., EQU S.sub.1 .fwdarw.C.sub.1 .fwdarw.S.sub.2 .fwdarw.S.sub.3
to define the profile A, (FIG. 6(a)), after which machining starting and end points, etc., of the part profile A are designated by a motion statement definition to define a tool path along which a tool is moved.
In the foregoing,
(1) signifies a circle of center (x.sub.3,y.sub.3) and radius r.sub.1 ;
(6) signifies a straight line passing through points P.sub.1, P.sub.2 ;
(4) signifies a left-side tangent line (straight line) of two tangent lines passing through point P.sub.1 and contacting the circle C.sub.1 ; and
(5) signifies a right-side tangent line (straight line) of two tangent lines passing through point P.sub.2 and contacting the circle C.sub.1. The character L is a qualifier meaning "left", and the character R is a qualifier meaning "right". There are two methods of figure definition. A first method entails defining points, straight lines and circles using absolute numeric data. A point is defined as EQU P=x, y
using the coordinates (x,y) of the point (see FIG. 7(a), a straight line is defined as EQU S=P.sub.1, P.sub.2 or S=x.sub.1, y.sub.1, x.sub.2, y.sub.2 using two points (x.sub.1,y.sub.1), (x.sub.2,y.sub.2) through which the straight line passes (see FIG. 7(b)), and a circle is defined as EQU C=x, y, r
using the coordinates (x,y) of the center of the circle and the radius r of the circle (see FIG. 7(c)).
The second method entails defining points, straight lines and circles using other elements (points, straight lines and circles) that have already been defined. For example, point P.sub.1 is defined as follows with reference to FIG. 7(d): EQU P.sub.1 =S, C, L
straight line S.sub.1 is defined as follows with reference to FIG. 7(e): EQU S.sub.1 =C.sub.1, C.sub.2, A
(the upper straight line tangent to two circles C.sub.1 and C.sub.2, where A is the qualifier meaning "upper"), and circle C is defined as follows with reference to FIG. 7(f): EQU C=S.sub.1, S.sub.2, S.sub.3
(a circle tangent to three straight lines). The foregoing method in which elements already defined are used to define other elements is only one example, there being many other methods of definition available.
When figure definition is performed in the prior art, the arrangement is such that a figure is defined by a first definition statement or, alternatively, an already defined figure is used to define another figure by a second definition statement. A figure defined by a second definition statement is re-expressed internally by the first definition statement, which uses coordinate data. Therefore, the second definition statement is erased. Consequently, in a case where it is desired to modify the part profile, as shown in FIG. 8, by changing the radius of the circular arc C.sub.1 of the profile A (see FIG. 6(a)), the figure is defined by the following part program: EQU C.sub.1 =x.sub.3, y.sub.3, r.sub.1 EQU P.sub.1 =x.sub.1, y.sub.1 EQU P.sub.2 =x.sub.2, y.sub.2 EQU S.sub.1 =P.sub.1, C.sub.1, L EQU S.sub.2 =P.sub.2, C.sub.1, R EQU S.sub.3 =P.sub.1, P.sub.2 EQU S.sub.1 EQU C.sub.1 EQU S.sub.2 EQU S.sub.3 EQU PEND
The prior art is such that the profile must be specified by redefining each figure element from the beginning and picking the figure elements in order along the profile. As a result, revising the already defined profile is a troublesome task.
Accordingly, an object of the present invention is to provide a profile revising method through which a profile can be revised merely by solely modifying the figure definition statement of a figure element relating to a modification.